In the manufacture of cable containing both electrical and optical fiber conductors used as mutually exclusive channels, the optical fiber and conventionally insulated metal conductors are helically wound to enable flexing of the cable without creating undue stresses on any one of the component metal conductors or optical fibers. Two opposing constraints, however, have prevented the production of satisfactory cables with small diameter. The optical fibers are restricted to bends having a radius of curvature greater than about 5 centimeters for efficient operation. In a small-diameter cable, this requires a long lay at a small angle to the axis of the cable. Metal conductors, by contrast, require a short lay with a relatively large angle to the axis of the cable. This is necessary to minimize the possibility of exceeding, during flexure of the cable, the elastic limit of the metal conductor. If the elastic limit of the metal conductor is exceeded, the individual conductors will hockle after the stresses are removed. Hockling occurs because the metal conductors are not restrained and are easily stretched to and beyond their elastic limit. Once hockling occurs, any further flexure of the cable would tend to break the hockled conductor and render the affected conductor, and possibly the whole cable, useless.
A need exists, therefore, for an assembly which enables the fabrication of small-diameter hybrid cables that are flexible and yet immune to hockling of the contained metal conductors.